NEW YORK ( TheStreet) -- An internal JPMorgan Chase ( JPM) e-mail message describing a meeting involving CEO Jamie Dimon and Banco Santander ( STD) boss Emilio Botin offers a fascinating glimpse into the banking industry, and may also be worthy of scrutiny for antitrust reasons.

The JPMorgan e-mail, sent on June 5, 2008, came to light recently in connection to litigation stemming from that company's acquisition of Washington Mutual from the Federal Deposit Insurance Corp. in September of that year in the biggest bank failure in the history of the American financial system.

Written by Jose Cerezo, an investment banker at JPMorgan, the e-mail describes the two bank bosses and a Santander executive board member, Juan Inciarte, talking about several possible acquisitions of interest to both banks at the time, including WaMu, Suntrust ( STI), PNC Financial ( PNC), and Wachovia (which was eventually acquired by Wells Fargo ( WFC)).

Jamie Dimon's Collusion?

"It is important to have an open dialogue with them, as Santander would not pursue any of these opportunities if JPMorgan were to do the same (can't compete on price with JPMorgan for an acquisition in the USA). But Santander would probably hire JPMorgan as advisor if we are not going after them," Cerezo writes.

The suggestion in the e-mail that the banks may be divvying up the market, or that Santander might reward JPMorgan with an advisory fee if it chose not to pursue a target of interest to both banks, is troubling, according to Ian Ayres, an economics and law professor at Yale University.

"The email is very problematic. If I were in the Justice Department I'd immediately open an investigation to pursue this further," Ayres said.

However, Ayres notes what he sees as a weakness in the U.S. Sherman Antitrust Act, which is that it is only violated if an actual anti-competitive agreement is put in place. That loophole famously allowed American Airlines ( AMR) to avoid penalty even after its chief executive was recorded openly proposing to a competitor that they both lower their prices simultaneously. The JPMorgan e-mail does not appear to prove an anti-competitive agreement existed between the two banks, Ayres says.

The Federal Trade Commission has argued it has broader powers under Section Five of the Federal Trade Commission Act, which prohibits "unfair methods of competition," according to William Page, a senior associate dean at University of Florida's law school who has written two books on anti-trust issues involving Microsoft ( MSFT).

Page would not say whether he thought the e-mail described illegal activity, or warranted further investigation, saying only that he found it "interesting."

"The fact that you have the heads of these two banks talking directly: whenever you have that kind of direct communication there's going to be some question about what it is they're actually discussing," Page says.

In addition to the banks mentioned above, the e-mail describes both bank chiefs as interested in buying Citigroup's ( C) Banamex unit. Santander confirmed it tried to buy Banamex but was told it was not for sale.

Dimon also advises Santander to "take a good look," at Citigroup's U.S. consumer finance business, a business Dimon likes but says "does not fit in any one of JPMorgan's key divisions."

Santander also wonders why JPMorgan does not attempt to acquire General Electric ( GE)'s GE Money unit in the United States. Cerezo reports Dimon as saying the fact that the credit card business is all private label makes it easy to lose to competitors, like JPMorgan.

Dimon also explained several reservations he has about doing business in China, including a relationship he describes as "a one-way street," with Chinese partners asking much and giving nothing in return.

Cerezo also describes the two bank chiefs as discussing various corporate governance issues, noting there is "obviously very good chemistry between Jamie and Botin, who would like to see him next time he is in New York."

Representatives from JPMorgan, Santander and the Department of Justice all declined comment for this story.